Hydraulic brake system



Sept. 2, 1952 R. BLAFIELD 2,609,067

HYDRAULIC BRAKE SYSTEM Filed March 14, 1950 2 Sl-IEETSSHEET l INVENTOR for BlflF/ft 0,

ATTORNEY? p 2, 1952 R. BLAFIELD 2,609,067

HYDRAULIC BRAKE SYSTEM Filed March 14, 1950 2 SHEETS-SHEET 2 INVENTOR Ear 54/071220,

BY o azz wmm ATTORNEY5 Patented Sept. 2, 1952 1 UNITED STATES PATENT OFFICE Q r 2,609,067 I YHYDRAULICBRAKE SYSTEM 7 Blafield,NewportNews,Va. Appli ation March14, 1950, Serial No; 149,543

The present invention relates to hydraulic brake systems for; automotive vehicles and more particularly to' a dual cylinder brake system where one of the cylinders, distributes the fluid.

a the, front wheels and the other cylinder distributes fluidto the rear Wheels.

vIt is a primaryobject ofthis invention to furnish a brake system-as described above, which maybe so arranged that either. one of 'the cylinders will operate the front and back wheels should the other of the cylinders become defective.

Another object of the invention is to provide a brake system whereby in the event one of the brake lines leading to either the front or rear sets of wheels becomes broken, theother set will continue to function.

Still another object of the present invention is to provide a pressure responsive means for actuating a signaling device should the pressure in either of the above described brake lines drop below a predetermined level.

The invention furthers contemplates the use of bypass means so that should one of the dual cylinders fail to function properly, it will not interfere with the functioning of the other cylinder.

Still further objects and advantages will become apparent from the following description of the present invention illustrated in the accom panying drawing, in which:

Figure 1 is aplan view of the present invention showing various parts in dotted line;

Figure 2 is a sectional View taken on line Z- -Z ofFig. 1; 1

Figure 3 is a diagrammatic plan of the brake. system as used in an automotivevericle;

Figure is-a perspective view of the device showing the control knobs and operating pedal;

Figure 5 is a sectional View taken on line 55" of Fig. 1, showing the valve in a closed position. Figure 6 is asectional'view of the device taken online 5 5 of Fig. 1, showing the valve in an open position; I r Similar-reference characters represent similar parts in the several figures.

The present invention has been designed to add many safety features to the hydraulic brake systems for automotive vehicles. At the present time the system on such vehicles are of a single flow variety. That is, one cylinder operates as a master and distributes fluid toj the various wheels for actuating pistons which operate the brake shoes. Should a break occur in any of the lines a pressure drop will occur in the other three lines, thereby resulting in failure of the,

whole system. Such failures are very common and often result in serious accidents. times what would be mere minor accidents often become very serious by a brake failure.

This can best be illustrated, for example, where a vehicle should strike a glancing blow on'anotherl vehicle, such blow resulting in the breaking of, a fluid line running to the wheel closest to where the blow is struck. Immediately the vehicle is out of control, resulting in serious damage to the vehicle and loss of life. This invention contem plates separating these lines into front and back pairs and providing a separate master. cylinder for each pair of lines. In this manner, should a break occur in one or" the lines at least two of the wheels will continue to have a braking function. Further, control means are provided so that in the event of a break in the line or a loss of fluid. into one of the brake drums, this line may be shut out of the system and the vehicle. will continue to operate with two wheel brakes until a repair shop is reached.

A signaling means has been provided which is actuated by a pressure responsive means in. the line of each of the master cylinders. By testing the brakes before starting or moving the vehicle, defects in the lines may be found which will put the operator on notice that one of the cylinders is not functioning properly. Also, in the event the quantity of fluid in the lines and reservoir is too low, this may also be detected.

One of the further causes of failure of they brake system is in piston or cylinder failure. Many times the master cylinder piston washer, after due time, wears away and causes the fluid to bypass the washer in question. Therefore, compression of liquid in the system cannot be maintained when the foot pedal is depressed. With the present invention such a failure would immediately come to the knowledge of the oper-. ator and could be quickly remedied.

The main portion of the device comprises a block In having dual pressure generating means therein including a pair of cylinders H and [2. These cylinders are arranged in the lower portion of the block and each is of the usual hydraulic type. Directly over each of the cylinders a reservoir is provided and, as seen in Fig. 2, is illustrated by the numeral 13. A filler plug l3a is provided in the top wall of the reservoir so that in the event of ,a. fluid leak in any of the lines Many " 3 reason for this wall is that in the case of a, break through 90 it will be seen that the flow or fluid in one of the fluid lines resulting in draining of in each passage can be cut fully on or fully oil. the fluid therefrom the complete reservoir will In order that one 01' the dual cylinders can not be drained. In view of the fact that each operate should the other of the cylinders become of the cylinders II and I2 is the same in con- 5 inoperative, or should it become necessarytoclose struction it is deemed that a description oi. one either of the passages 28 or 29, a bypass has been ill b m i t provided for connecting the reservoir l3 and the Between the reservoir l3 and the cylinder l4, passages 28 and 29. As seen in Fig. 2, the bypass a port I5 is furnished for interconnection be- Co p a horizontal p ssage 49 in the block tween theecylinden and: the reservoir. Cylinders: and :a vertical passage '.5n1' in valve stem 33. l l and 12 vide w th i t d" I1, Therefore,- it will be seen that in the event the respectively, each having a. leather washer to stem 33 should be positioned 80 s to ose the prevent leakage around the piston. For operat p a e 28, as ow in F t e u d going ing each of the pistons the brakenpedal, I8, is nt the passa e 8 f m the ylind r is allowed operatively connected thereto, the linkage in- 1'5 110 fi wup' 'ou h the pa sage 50 and the horicluding a bell crank lever which is pivotallyi': nt 'l passage 49 back into the reservoir. mounted, as at H], to a forwardly extending mem= A second pa f Vertical passages are p ovided ber 20, the latter being mounted on the forward inthehorizonta-l pass es 28 and 29. one or which end of the main block In. Piston rods 2 I; and'22 is ated by the numeral 5! in Fi 2. Circuit are secured to the pistons-i6 and I1, respectively, closing vi s 52 and 53 are mounted at the andnzextending throughtthe forward end. of the pper e d Of pa sa es and they are adapted. monk, illustrated by t 1 z3, in bearjng, to be electrically connected by means of wires 54 members 24. and 25,.respectively. Thaforyvard' anal-55 're e iv yi nd cating lightson-the endpf, each of. the pistonrods. is connected-by a dash, aslillustraitedy eumeral '56. It'will transyersercd. 21., and. an. intermediate .1ink-..26. be Seen-that d phra m: slisada'pte'd to'recelve' is, provided.,to,pivotally. connect the lower endofj pressure p se f Om' t e ys em at s, thebrake pedalsbellcrankand.the.transverserod,. When the pr ssure" in the system rises the diathelatterconnectionbeingmidway of..the,endjoff, phragm'isactua ed'to ther byicl s'e the circuit their-Mm. and operate one of' the lights on the dash 56. Rearwardly ofieach of the cylinders inth'emain To'summarize'the' flperatlon of the present in block. llllpassages." and-29are provided, these, Ventlonv Will e u necessary to determine passages providing; communication bet th Where a defect irrthe systemoccurs and the man'-' reanwheeldistributing line an and the front wheel. nerm' w wisolate h 'br k from the system. distributingJine 3l;.respectively, and the master p Should p s o l6' fail to operate'it': cylinders; a nd' [2 respectively Conventional would be necessary to turn the Stein/33 relicLvalves are furnished in each of the passages, closed posit omturn the m 5 1 11 1 D onem which is I illustrated by. the numeral 28b. t1on and then cylinder [1 could'operatethe brake Rassages 2,8.Jandf29'are.intereconnected intermedrllms of all he' W eels until the defective diateth'eiriendsjbyacrossover passage 32. Pas-v cyhllder ls'l'epalledv v and are controlled respectively In eYent One Of the piStOnsShOuld by vertically extending valves including valve i 13151701143, the force of pressure'in' the stems. 33, .34 and 35. These stems are adapted hne and in the P e 28'W0uld fall so that to rotate in vertical passages in'the block.. These w "l p a P d downwardly th vertical passages. extend from thelower end por-v dlaphllagm 57W0u1d not function and the light tionpf the block past eachof the horizontal pase, dash would fall to Operate. Depending sages.,to the upper surface of the block. As will Qh 'pf the lights fails o Op r te the be'seen fromFig. 2 the .passagereceiving the valve. invermould n tell which part of thesystem stem- 33has a lower end wall, illustratedxby the. 9 'l l Y h e 30 should break the numerai'36, andextends up through the passage. hghtlwould slmilarly fail 'operateandit would From the latter passage to the upper surface; then be necessary to clo'sethe stem 33' and leave ofpthe ortvthe open end'of the passage,- the cross-overstem 35 in itsclosed position. In a*wall-31 surrounds the valve-stem. Securing the. thls manner the i e will still control va1ve...stems position; bony, 39 and. front wheels-and thus braking service is provided provided-"and are 'adapted to surround each of m t hne E fe fi of OurSe, in the thestemshtherebemg appropriate packing-glands 5 event of suchlme'faflure' the circuit of the'sign'al between-the stems'an'd. the bolts.; A control arm a open; Therefore; the t" isprovided for each ofthe aforementioned stems on h panel would not operate; which would be as' illustratedrbythe numerals 38a, 39d and 40a.-. thesigvnal thatmwfthe Pairs ofwheels had'no' In the lowerportion oheach of the valvestems. i i fi V v horizontallyextending apertures are provided so 2 2 be seenthat I e prqvideda novel that when the stem is in a certain position fluid g 's l' Q vehicl?s hevmg many is allowed-to flow through the.passage s ,and in. ergnt advantages making fPr'added'safety Uh another position'the flow of fluid is cutvofLfrom. i li i 9 i be adapted th'epassages; These apertures are illustratedjoy. an mo 1 e or truck Wlth only small hange being ther'numeral 4| 'instem 33iand the numeral .42 necessary This systemis capable of y V lle-- v in-'-the-stem 35.1; In theupper surfaceof the block. $3 5 3. 35 3 3 :12 g event of partial adjacentthe outer end of the .stem .controlling. While I have shown g gggg igd g gg gi; err

arms; .vertical1y. extending postsare... provided, f r of my imention.v it will beunderstoodthat being arranged so as,to.,..provide a stop-,means. allowing 90 rotation of each, stem. The stops or 7 gigijifiiigfffifii$3 1,135,253???WW. posts :forstem .33 are illustrated by thenumerals appended, claims e ned 43-'a nd 44; those for stem .34 being illustratedby. I the-numeralsfiand 46 andthe stopmeansfor. In a stem 35ibeingiillustrated by thenumeralsill and; 11 v,fmngand 48 5;rj ,Byi"iallowingreach of the. stems torotate. dual pressuregen ystem. for -vehicles having pairs r brakes, a main block-having? crating; means positionedthere' in and means forming a reservoir, a communi eating passage in said block leading from one of said pressure generating means to a fluid line connected to the rear pair of wheel brakes, a second passage in said block leading from the other of said pressure generating means to a fluid line connected to the front pair of wheel brakes, a bypass leading from each of said passages to said reservoir, valve means positioned in each of said bypasses and its respective passage, said valve means controlling the flow of fluid through each bypass and its respective passage and being so constructed that if the passage is closed the bypass will be open and if the passage is open the bypass will be closed, and a cross-over control means for selectively operating both of said pairs of wheel brakes from a single one of said generating means.

2. In a brake system for vehicles having front and rear sets of wheel brakes, separate fluid pressure generating means for each set of brakes, a fluid reservoir for supplying fluid to each of said pressure generating means, means controlling the flow of fluid from each of said pressure generating means to its respective set of brakes, a bypass between each of the pressure generating means and said reservoir so arranged that in the event either of said fluid control means is closed the fluid will return to the reservoir, and a cross-over control means for selectively operating both sets of front and rear brakes from a single one of said generating means.

3. In a brake system for vehicles having pairs of front and rear wheel brakes, dual pressure generating means, a fluid reservoir for supplying fluid to each of said pressure generating means, a fluid line leading from one of said generating means to said front pair of brakes and a second fluid line leading from the other of said generating means to said rear pair of brakes, valve means inserted in each of said fluid lines for controlling the flow of fluid from each pressure generating means to its respective set of brakes, a bypass interconnecting each of said pressure generating means and said reservoir, the flow of fluid through each bypass being controlled by one of said valve means, and a cross-over control means for selectively operating both of said pairs of brakes from a single one of said generating means.

4. In a brake system for vehicles having sets of front and rear wheel brakes, a main block having dual fluid pressure generating means positioned in a lower portion thereof, a fluid reservoir in said block mounted over said generating means, a passage leading from each of said pressure generating means for communication with separate sets of brakes, a bypass means providing communication between said reservoir and each of said passages, valve means positioned in each of said passages and their respective bypass means controlling the flow of fluid therethrough, and a cross-over passage in said block providing communication between each of said passages, and control means positioned in said cross-over passage for controlling the flow of fluid therethrough so that both said sets of brakes may be operated from a single one of said pressure generating means.

ROY BLAFIELD.

REFERENCES CITED The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,606,224 Hoeller Nov. 9, 1926 1,695,194 Lansinger Dec. 11, 1928 1,978,669 Carroll Oct. 30, 1934 2,074,718 Bohannan Mar. 23, 1937 2,246,814 Rehm June 24, 1941 2,332,301 Cox Oct. 19, 1943 

